surprising abel_nf failures

Stream: mathlib4

[Floris van Doorn]

I don't know the exact scope of abel_nf and I'm only using it through noncomm_ring, but I expected the following to succeed (or at least, abel_nf to make some kind of progress):

import Mathlib.Tactic.Abel

example {R} [Ring R] : (0 : R) + 1 = 1 := by abel_nf -- (abel does work)
example {R} [Ring R] : (0 : R) + 1 = 1 ∧ (1 : R) + 0 = 1 := by abel_nf